To localize spermidine- and ethidium-binding sites in tRNA and effects of such binding on tRNA conformation and activity. To study role of polyamines in structure and synthesis of bacteriophage R17. To determine if polyamines are similarly involved in a picornavirus which multiplies in animal cells. To determine the source of the apparently procaryotic polyamine in the biosynthesis of turnip yellow mosaic virus and to see if procaryotes can support the multiplication of this virus. To study controls of polyamine synthesis in E. coli. To study the effects of various inhibitors of polyamine synthesis on the growth and multiplication of animal cells.